The bracing apparatus described in German patent 26 51 028 for support of a roll over the length of its working surface has several supporting members distributed longitudinally, which are provided with shell-like bearing pockets on their surfaces facing or adjacent the surface of the roll being supported which are connected to pressurized medium lines.
The pressurized medium fed to the bearing pockets of the supporting members by the pressurized medium lines is fed via control valves with mechanical sensors, which are mounted at both ends of the supported roll and which detect the position of the ends of the roll.
As soon as the roll moves from its set position in one or the other direction, the pressure of the pressurized medium in the pressurized medium lines is reduced by the control valves and thus the roll is brought back to its original set point position.
This known roll bracing apparatus has the disadvantage that the supporting members spaced adjacent each other allow only a minimal use of the available supporting surface. The degree of roll bracing is correspondingly comparatively small and can be adjusted to the requirements only by excessive pump pressure. This of course involves a comparatively high energy consumption and is expensive.
Furthermore the flow of the pressurized medium depends on the load experienced by the working roll during operation, which requires a special variable pump control. The pressurized medium flow, continuously changing in its value depending on the load experienced by the working roll, disadvantageously affects the cooling of the rolls. Finally in this known roll bracing apparatus on both ends of the roll control valves with mechanical sensors reducing the roll bracing surfaces are required to hold the roll in its preset working position.